Thursday, April 28, 2016

As part of the project's ongoing research of behavioral development in spotted hyenas, we perform numerous tests to determine how variation in social rank, maternal care, park management and clan stability can affect cubs as they mature. You have probably already read in previous posts about how we present eggs and powdered milk to determine how aggressive different cubs can be, as well as determining how long it takes individuals to act their rank. This helps us to understand both a cub's budding aggressive and submissive personalities, as well as variation in the speed of leaning their social rank.

Another trait we are interested in is neopobia (the fear of new things), which can influence and individual's ability to learn through exploration of novel environments and situations, as well as being somewhat related to an individual's overall boldness. For example: in wild starlings, individuals that are quicker to approach and feed near novel stimuli are also faster at solving problems focused on foraging ability (Boogert et al. 2006), these were also typically individuals with the highest ranks. This is similar to what has been seen in captive coyotes when more dominant individuals were the only individuals willing to enter a novel environment to feed (Mettler and Shivik, 2006). However, dominant individuals are not always those willing to take the risk of exploring a novel object or environment, as seen in black-capped chickadees where the subordinate individuals were less neophobic than dominant individuals (Seok An et al, 2011). Despite seeing differences in how neophobia relates to social rank, all of these studies did observe individual differences outside of rank, which may or may not be due to the social environment they were raised in.

This is where our study comes in, as we can test all of these influences (rank, personality, etc), and where the fun begins. In order to test neophobia you need to present animals with something that they have never seen or experienced before (i.e. a novel object). What better excuse would I ever have to present hyena cubs toys!!! Therefore, over the next few years I will be running back and forth between clans, finding cubs, and giving them new objects to explore and observing their reactions.

Here is MJAG, a low ranking hyena from the South Clan, who took about 20 minutes to get just close enough to sniff the funnel. As you can see, MJAG is fairly reluctant to get too close, as he is staying as far away as possible, while still being able to sniff the funnel and touch it with his nose.

In comparison, these cubs from the North clan swarmed the funnel in about a minute, and I actually had to chase after them in the car when the ran away with it.

Finally, we have HEMI from the Talek West clan, who didn't even approach the funnel, and then took a nap after a few minutes completely ignoring it.

Of course we do repeated samples on different days with different novel objects each time to see if responses are similar, and as you can see MJAG is still curious but a bit spooky.

I had to rescue the novel object from the North cubs again.

And the Talek cubs were still too afraid to get closer than a few meters.

I still have a long way to go to begin to detect individual and rank differences in the amount of neophobia presented by those that get to interact with a novel objects, but even with just a few trials you can see how clans may vary.

Don't think I have forgotten about the individuals that have left the den. Adults and sub-adults found alone in the field are presented with novel objects are well. This include the random "toys" that we present to the cubs, as well as objects that require the hyena to perform a task to get a treat. Below is the beginning of one of these objects where hyenas can earn an award that was designed by graduate student Lily Johnson-Ulrich.

This opaque tube has a treat inside. The task is for the hyena to approach the tube, and then reach into one of the sides to grab the treat. In contrast to a single presentation of a novel object, we will continue to to present this tube to the hyena until it becomes comfortable with solving the task. Once they are comfortable with the opaque tube, we will present the hyena with a tube of the exact same dimensions that is completely clear (i.e. they can see the treat through the tube) to see if they can inhibit their response to grab at the food through the clear tube, or remember that they have to go around to the side of the tube to reach in and grab the treat. This task represents both an individual's ability to respond and approach a novel object in their environment, as well as solving a cognitive task. As you can see here we are just getting started with the opaque tube, and the hyenas are treating this as a novel object in their environment. Nali (above) never approached the tube closer than 25 meters. VOYA (below) came closer to the tube, but never touched it.

It will probably take us some time to get these individuals used to the tube, and when Lily comes out in a month we will start presenting the hyenas with the clear tube. Stay tuned until then, and don't worry there will be a post in the future with all of the bloopers resulting from crazy cubs, and annoying sub-adults, running around with toys.

Help Support the Research

You can help support our research by making a donation to the Hyena Research Fund at MSU. Your contributions provide necessary resources for the students and scientists to continue our work. Use the link below to make a donation or contact MSU for additional details.